Turkey applied to the European Economic Community (EEC), founded in 1958, for full membership in July 1959. The Ankara Agreement, which would be valid until the full membership conditions were met, was signed on September 12, 1963.

Turkey’s candidacy for full membership was registered at the Helsinki Summit, held on December 10-11, 1999. During the European Union Summit of Heads of States and Governments held in Brussels on December 16-17, 2004, it was agreed that membership negotiations would start on October 3, 2005. After the negotiations had started, the relations with the EU diversified and intensified. Within this mindset, the Assembly has become one of the prominent actors.

According to Article 27 of the Ankara Agreement, based on the decision of the Turkey-EEC Association Council dated July 27, 1965, the Turkey-European Union Joint Parliamentary Committee was established. The committee's duty is to address issues related to Turkey's EU accession process and to strengthen relations between the GNAT and the European Parliament.

The EU Harmonization Committee was established in 2003 in the Grand National Assembly in order to monitor developments regarding the EU accession process and to negotiate, and to follow the developments in the EU and to inform the GNAT about these developments. The committee is also responsible for carrying out relations with the EU institutions and parliaments of other member states and candidate countries, and the EU committees.

The Grand National Assembly has been participating in meetings of COSAC since 2003. COSAC serves as a platform for exchanging views and discussing issues of common concern in the development of inter-parliamentary cooperation with the members of the EU member states and candidate countries with EU affairs committees.

The Grand National Assembly of Turkey participates in joint projects to strengthen the institutional capacity in cooperation with the EU and organizes joint seminars and study visits with the EU Commission Directorate General for Enlargement and Technical Assistance and Information Exchange Unit (TAIEX).

In the framework of the EU Inter-Parliamentary Information Exchange Program (IPEX), EU countries are regularly informed of the activities of the Assembly.

Within the EU Visitors Programs, parliamentary staff participates in the internship programs in order to have a better understanding of the European Parliament and the EU institutions.

The EU's relations with the GNAT are conducted through the EU Harmonization Committee and the Turkey - European Union Joint Parliamentary Committee.